By matching the results of joint friction tests and the physical- chemical fractionation of bovine synovial fluid a hyaluronate-free lubricating fraction has been isolated and partially characterized. Using this same approach this lubricating component will be further isolated and identified and the methods applied to human synovial fluid. One of the moieties of the cartilage lubricating fraction is suspected of being cartilagenous in origin. This will be fully investigated, initially in the bovine system, and if the hypothesis is borne out such fractions will be isolated and quantitated in human normal and diseased articular cartilage as well. The effects of hyaluronic acid in retarding joint wear in vitro will also be studied. The overall object is to understand joint lubrication fully enough to develop techniques to allow meaningful clinical intervention in cases of joint degeneration and to suggest improved bearing surface characteristics for total joint replacements.